| /* Perform simple optimizations to clean up the result of reload. |
| Copyright (C) 1987-2017 Free Software Foundation, Inc. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it under |
| the terms of the GNU General Public License as published by the Free |
| Software Foundation; either version 3, or (at your option) any later |
| version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "backend.h" |
| #include "target.h" |
| #include "rtl.h" |
| #include "tree.h" |
| #include "predict.h" |
| #include "df.h" |
| #include "memmodel.h" |
| #include "tm_p.h" |
| #include "optabs.h" |
| #include "regs.h" |
| #include "emit-rtl.h" |
| #include "recog.h" |
| |
| #include "cfgrtl.h" |
| #include "cfgbuild.h" |
| #include "cfgcleanup.h" |
| #include "reload.h" |
| #include "cselib.h" |
| #include "tree-pass.h" |
| #include "dbgcnt.h" |
| |
| static int reload_cse_noop_set_p (rtx); |
| static bool reload_cse_simplify (rtx_insn *, rtx); |
| static void reload_cse_regs_1 (void); |
| static int reload_cse_simplify_set (rtx, rtx_insn *); |
| static int reload_cse_simplify_operands (rtx_insn *, rtx); |
| |
| static void reload_combine (void); |
| static void reload_combine_note_use (rtx *, rtx_insn *, int, rtx); |
| static void reload_combine_note_store (rtx, const_rtx, void *); |
| |
| static bool reload_cse_move2add (rtx_insn *); |
| static void move2add_note_store (rtx, const_rtx, void *); |
| |
| /* Call cse / combine like post-reload optimization phases. |
| FIRST is the first instruction. */ |
| |
| static void |
| reload_cse_regs (rtx_insn *first ATTRIBUTE_UNUSED) |
| { |
| bool moves_converted; |
| reload_cse_regs_1 (); |
| reload_combine (); |
| moves_converted = reload_cse_move2add (first); |
| if (flag_expensive_optimizations) |
| { |
| if (moves_converted) |
| reload_combine (); |
| reload_cse_regs_1 (); |
| } |
| } |
| |
| /* See whether a single set SET is a noop. */ |
| static int |
| reload_cse_noop_set_p (rtx set) |
| { |
| if (cselib_reg_set_mode (SET_DEST (set)) != GET_MODE (SET_DEST (set))) |
| return 0; |
| |
| return rtx_equal_for_cselib_p (SET_DEST (set), SET_SRC (set)); |
| } |
| |
| /* Try to simplify INSN. Return true if the CFG may have changed. */ |
| static bool |
| reload_cse_simplify (rtx_insn *insn, rtx testreg) |
| { |
| rtx body = PATTERN (insn); |
| basic_block insn_bb = BLOCK_FOR_INSN (insn); |
| unsigned insn_bb_succs = EDGE_COUNT (insn_bb->succs); |
| |
| /* If NO_FUNCTION_CSE has been set by the target, then we should not try |
| to cse function calls. */ |
| if (NO_FUNCTION_CSE && CALL_P (insn)) |
| return false; |
| |
| if (GET_CODE (body) == SET) |
| { |
| int count = 0; |
| |
| /* Simplify even if we may think it is a no-op. |
| We may think a memory load of a value smaller than WORD_SIZE |
| is redundant because we haven't taken into account possible |
| implicit extension. reload_cse_simplify_set() will bring |
| this out, so it's safer to simplify before we delete. */ |
| count += reload_cse_simplify_set (body, insn); |
| |
| if (!count && reload_cse_noop_set_p (body)) |
| { |
| if (check_for_inc_dec (insn)) |
| delete_insn_and_edges (insn); |
| /* We're done with this insn. */ |
| goto done; |
| } |
| |
| if (count > 0) |
| apply_change_group (); |
| else |
| reload_cse_simplify_operands (insn, testreg); |
| } |
| else if (GET_CODE (body) == PARALLEL) |
| { |
| int i; |
| int count = 0; |
| rtx value = NULL_RTX; |
| |
| /* Registers mentioned in the clobber list for an asm cannot be reused |
| within the body of the asm. Invalidate those registers now so that |
| we don't try to substitute values for them. */ |
| if (asm_noperands (body) >= 0) |
| { |
| for (i = XVECLEN (body, 0) - 1; i >= 0; --i) |
| { |
| rtx part = XVECEXP (body, 0, i); |
| if (GET_CODE (part) == CLOBBER && REG_P (XEXP (part, 0))) |
| cselib_invalidate_rtx (XEXP (part, 0)); |
| } |
| } |
| |
| /* If every action in a PARALLEL is a noop, we can delete |
| the entire PARALLEL. */ |
| for (i = XVECLEN (body, 0) - 1; i >= 0; --i) |
| { |
| rtx part = XVECEXP (body, 0, i); |
| if (GET_CODE (part) == SET) |
| { |
| if (! reload_cse_noop_set_p (part)) |
| break; |
| if (REG_P (SET_DEST (part)) |
| && REG_FUNCTION_VALUE_P (SET_DEST (part))) |
| { |
| if (value) |
| break; |
| value = SET_DEST (part); |
| } |
| } |
| else if (GET_CODE (part) != CLOBBER |
| && GET_CODE (part) != USE) |
| break; |
| } |
| |
| if (i < 0) |
| { |
| if (check_for_inc_dec (insn)) |
| delete_insn_and_edges (insn); |
| /* We're done with this insn. */ |
| goto done; |
| } |
| |
| /* It's not a no-op, but we can try to simplify it. */ |
| for (i = XVECLEN (body, 0) - 1; i >= 0; --i) |
| if (GET_CODE (XVECEXP (body, 0, i)) == SET) |
| count += reload_cse_simplify_set (XVECEXP (body, 0, i), insn); |
| |
| if (count > 0) |
| apply_change_group (); |
| else |
| reload_cse_simplify_operands (insn, testreg); |
| } |
| |
| done: |
| return (EDGE_COUNT (insn_bb->succs) != insn_bb_succs); |
| } |
| |
| /* Do a very simple CSE pass over the hard registers. |
| |
| This function detects no-op moves where we happened to assign two |
| different pseudo-registers to the same hard register, and then |
| copied one to the other. Reload will generate a useless |
| instruction copying a register to itself. |
| |
| This function also detects cases where we load a value from memory |
| into two different registers, and (if memory is more expensive than |
| registers) changes it to simply copy the first register into the |
| second register. |
| |
| Another optimization is performed that scans the operands of each |
| instruction to see whether the value is already available in a |
| hard register. It then replaces the operand with the hard register |
| if possible, much like an optional reload would. */ |
| |
| static void |
| reload_cse_regs_1 (void) |
| { |
| bool cfg_changed = false; |
| basic_block bb; |
| rtx_insn *insn; |
| rtx testreg = gen_rtx_REG (word_mode, LAST_VIRTUAL_REGISTER + 1); |
| |
| cselib_init (CSELIB_RECORD_MEMORY); |
| init_alias_analysis (); |
| |
| FOR_EACH_BB_FN (bb, cfun) |
| FOR_BB_INSNS (bb, insn) |
| { |
| if (INSN_P (insn)) |
| cfg_changed |= reload_cse_simplify (insn, testreg); |
| |
| cselib_process_insn (insn); |
| } |
| |
| /* Clean up. */ |
| end_alias_analysis (); |
| cselib_finish (); |
| if (cfg_changed) |
| cleanup_cfg (0); |
| } |
| |
| /* Try to simplify a single SET instruction. SET is the set pattern. |
| INSN is the instruction it came from. |
| This function only handles one case: if we set a register to a value |
| which is not a register, we try to find that value in some other register |
| and change the set into a register copy. */ |
| |
| static int |
| reload_cse_simplify_set (rtx set, rtx_insn *insn) |
| { |
| int did_change = 0; |
| int dreg; |
| rtx src; |
| reg_class_t dclass; |
| int old_cost; |
| cselib_val *val; |
| struct elt_loc_list *l; |
| enum rtx_code extend_op = UNKNOWN; |
| bool speed = optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn)); |
| |
| dreg = true_regnum (SET_DEST (set)); |
| if (dreg < 0) |
| return 0; |
| |
| src = SET_SRC (set); |
| if (side_effects_p (src) || true_regnum (src) >= 0) |
| return 0; |
| |
| dclass = REGNO_REG_CLASS (dreg); |
| |
| /* When replacing a memory with a register, we need to honor assumptions |
| that combine made wrt the contents of sign bits. We'll do this by |
| generating an extend instruction instead of a reg->reg copy. Thus |
| the destination must be a register that we can widen. */ |
| if (MEM_P (src) |
| && (extend_op = load_extend_op (GET_MODE (src))) != UNKNOWN |
| && !REG_P (SET_DEST (set))) |
| return 0; |
| |
| val = cselib_lookup (src, GET_MODE (SET_DEST (set)), 0, VOIDmode); |
| if (! val) |
| return 0; |
| |
| /* If memory loads are cheaper than register copies, don't change them. */ |
| if (MEM_P (src)) |
| old_cost = memory_move_cost (GET_MODE (src), dclass, true); |
| else if (REG_P (src)) |
| old_cost = register_move_cost (GET_MODE (src), |
| REGNO_REG_CLASS (REGNO (src)), dclass); |
| else |
| old_cost = set_src_cost (src, GET_MODE (SET_DEST (set)), speed); |
| |
| for (l = val->locs; l; l = l->next) |
| { |
| rtx this_rtx = l->loc; |
| int this_cost; |
| |
| if (CONSTANT_P (this_rtx) && ! references_value_p (this_rtx, 0)) |
| { |
| if (extend_op != UNKNOWN) |
| { |
| wide_int result; |
| |
| if (!CONST_SCALAR_INT_P (this_rtx)) |
| continue; |
| |
| switch (extend_op) |
| { |
| case ZERO_EXTEND: |
| result = wide_int::from (rtx_mode_t (this_rtx, |
| GET_MODE (src)), |
| BITS_PER_WORD, UNSIGNED); |
| break; |
| case SIGN_EXTEND: |
| result = wide_int::from (rtx_mode_t (this_rtx, |
| GET_MODE (src)), |
| BITS_PER_WORD, SIGNED); |
| break; |
| default: |
| gcc_unreachable (); |
| } |
| this_rtx = immed_wide_int_const (result, word_mode); |
| } |
| |
| this_cost = set_src_cost (this_rtx, GET_MODE (SET_DEST (set)), speed); |
| } |
| else if (REG_P (this_rtx)) |
| { |
| if (extend_op != UNKNOWN) |
| { |
| this_rtx = gen_rtx_fmt_e (extend_op, word_mode, this_rtx); |
| this_cost = set_src_cost (this_rtx, word_mode, speed); |
| } |
| else |
| this_cost = register_move_cost (GET_MODE (this_rtx), |
| REGNO_REG_CLASS (REGNO (this_rtx)), |
| dclass); |
| } |
| else |
| continue; |
| |
| /* If equal costs, prefer registers over anything else. That |
| tends to lead to smaller instructions on some machines. */ |
| if (this_cost < old_cost |
| || (this_cost == old_cost |
| && REG_P (this_rtx) |
| && !REG_P (SET_SRC (set)))) |
| { |
| if (extend_op != UNKNOWN |
| && REG_CAN_CHANGE_MODE_P (REGNO (SET_DEST (set)), |
| GET_MODE (SET_DEST (set)), word_mode)) |
| { |
| rtx wide_dest = gen_rtx_REG (word_mode, REGNO (SET_DEST (set))); |
| ORIGINAL_REGNO (wide_dest) = ORIGINAL_REGNO (SET_DEST (set)); |
| validate_change (insn, &SET_DEST (set), wide_dest, 1); |
| } |
| |
| validate_unshare_change (insn, &SET_SRC (set), this_rtx, 1); |
| old_cost = this_cost, did_change = 1; |
| } |
| } |
| |
| return did_change; |
| } |
| |
| /* Try to replace operands in INSN with equivalent values that are already |
| in registers. This can be viewed as optional reloading. |
| |
| For each non-register operand in the insn, see if any hard regs are |
| known to be equivalent to that operand. Record the alternatives which |
| can accept these hard registers. Among all alternatives, select the |
| ones which are better or equal to the one currently matching, where |
| "better" is in terms of '?' and '!' constraints. Among the remaining |
| alternatives, select the one which replaces most operands with |
| hard registers. */ |
| |
| static int |
| reload_cse_simplify_operands (rtx_insn *insn, rtx testreg) |
| { |
| int i, j; |
| |
| /* For each operand, all registers that are equivalent to it. */ |
| HARD_REG_SET equiv_regs[MAX_RECOG_OPERANDS]; |
| |
| const char *constraints[MAX_RECOG_OPERANDS]; |
| |
| /* Vector recording how bad an alternative is. */ |
| int *alternative_reject; |
| /* Vector recording how many registers can be introduced by choosing |
| this alternative. */ |
| int *alternative_nregs; |
| /* Array of vectors recording, for each operand and each alternative, |
| which hard register to substitute, or -1 if the operand should be |
| left as it is. */ |
| int *op_alt_regno[MAX_RECOG_OPERANDS]; |
| /* Array of alternatives, sorted in order of decreasing desirability. */ |
| int *alternative_order; |
| |
| extract_constrain_insn (insn); |
| |
| if (recog_data.n_alternatives == 0 || recog_data.n_operands == 0) |
| return 0; |
| |
| alternative_reject = XALLOCAVEC (int, recog_data.n_alternatives); |
| alternative_nregs = XALLOCAVEC (int, recog_data.n_alternatives); |
| alternative_order = XALLOCAVEC (int, recog_data.n_alternatives); |
| memset (alternative_reject, 0, recog_data.n_alternatives * sizeof (int)); |
| memset (alternative_nregs, 0, recog_data.n_alternatives * sizeof (int)); |
| |
| /* For each operand, find out which regs are equivalent. */ |
| for (i = 0; i < recog_data.n_operands; i++) |
| { |
| cselib_val *v; |
| struct elt_loc_list *l; |
| rtx op; |
| |
| CLEAR_HARD_REG_SET (equiv_regs[i]); |
| |
| /* cselib blows up on CODE_LABELs. Trying to fix that doesn't seem |
| right, so avoid the problem here. Similarly NOTE_INSN_DELETED_LABEL. |
| Likewise if we have a constant and the insn pattern doesn't tell us |
| the mode we need. */ |
| if (LABEL_P (recog_data.operand[i]) |
| || (NOTE_P (recog_data.operand[i]) |
| && NOTE_KIND (recog_data.operand[i]) == NOTE_INSN_DELETED_LABEL) |
| || (CONSTANT_P (recog_data.operand[i]) |
| && recog_data.operand_mode[i] == VOIDmode)) |
| continue; |
| |
| op = recog_data.operand[i]; |
| if (MEM_P (op) && load_extend_op (GET_MODE (op)) != UNKNOWN) |
| { |
| rtx set = single_set (insn); |
| |
| /* We might have multiple sets, some of which do implicit |
| extension. Punt on this for now. */ |
| if (! set) |
| continue; |
| /* If the destination is also a MEM or a STRICT_LOW_PART, no |
| extension applies. |
| Also, if there is an explicit extension, we don't have to |
| worry about an implicit one. */ |
| else if (MEM_P (SET_DEST (set)) |
| || GET_CODE (SET_DEST (set)) == STRICT_LOW_PART |
| || GET_CODE (SET_SRC (set)) == ZERO_EXTEND |
| || GET_CODE (SET_SRC (set)) == SIGN_EXTEND) |
| ; /* Continue ordinary processing. */ |
| /* If the register cannot change mode to word_mode, it follows that |
| it cannot have been used in word_mode. */ |
| else if (REG_P (SET_DEST (set)) |
| && !REG_CAN_CHANGE_MODE_P (REGNO (SET_DEST (set)), |
| GET_MODE (SET_DEST (set)), |
| word_mode)) |
| ; /* Continue ordinary processing. */ |
| /* If this is a straight load, make the extension explicit. */ |
| else if (REG_P (SET_DEST (set)) |
| && recog_data.n_operands == 2 |
| && SET_SRC (set) == op |
| && SET_DEST (set) == recog_data.operand[1-i]) |
| { |
| validate_change (insn, recog_data.operand_loc[i], |
| gen_rtx_fmt_e (load_extend_op (GET_MODE (op)), |
| word_mode, op), |
| 1); |
| validate_change (insn, recog_data.operand_loc[1-i], |
| gen_rtx_REG (word_mode, REGNO (SET_DEST (set))), |
| 1); |
| if (! apply_change_group ()) |
| return 0; |
| return reload_cse_simplify_operands (insn, testreg); |
| } |
| else |
| /* ??? There might be arithmetic operations with memory that are |
| safe to optimize, but is it worth the trouble? */ |
| continue; |
| } |
| |
| if (side_effects_p (op)) |
| continue; |
| v = cselib_lookup (op, recog_data.operand_mode[i], 0, VOIDmode); |
| if (! v) |
| continue; |
| |
| for (l = v->locs; l; l = l->next) |
| if (REG_P (l->loc)) |
| SET_HARD_REG_BIT (equiv_regs[i], REGNO (l->loc)); |
| } |
| |
| alternative_mask preferred = get_preferred_alternatives (insn); |
| for (i = 0; i < recog_data.n_operands; i++) |
| { |
| machine_mode mode; |
| int regno; |
| const char *p; |
| |
| op_alt_regno[i] = XALLOCAVEC (int, recog_data.n_alternatives); |
| for (j = 0; j < recog_data.n_alternatives; j++) |
| op_alt_regno[i][j] = -1; |
| |
| p = constraints[i] = recog_data.constraints[i]; |
| mode = recog_data.operand_mode[i]; |
| |
| /* Add the reject values for each alternative given by the constraints |
| for this operand. */ |
| j = 0; |
| while (*p != '\0') |
| { |
| char c = *p++; |
| if (c == ',') |
| j++; |
| else if (c == '?') |
| alternative_reject[j] += 3; |
| else if (c == '!') |
| alternative_reject[j] += 300; |
| } |
| |
| /* We won't change operands which are already registers. We |
| also don't want to modify output operands. */ |
| regno = true_regnum (recog_data.operand[i]); |
| if (regno >= 0 |
| || constraints[i][0] == '=' |
| || constraints[i][0] == '+') |
| continue; |
| |
| for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) |
| { |
| enum reg_class rclass = NO_REGS; |
| |
| if (! TEST_HARD_REG_BIT (equiv_regs[i], regno)) |
| continue; |
| |
| set_mode_and_regno (testreg, mode, regno); |
| |
| /* We found a register equal to this operand. Now look for all |
| alternatives that can accept this register and have not been |
| assigned a register they can use yet. */ |
| j = 0; |
| p = constraints[i]; |
| for (;;) |
| { |
| char c = *p; |
| |
| switch (c) |
| { |
| case 'g': |
| rclass = reg_class_subunion[rclass][GENERAL_REGS]; |
| break; |
| |
| default: |
| rclass |
| = (reg_class_subunion |
| [rclass] |
| [reg_class_for_constraint (lookup_constraint (p))]); |
| break; |
| |
| case ',': case '\0': |
| /* See if REGNO fits this alternative, and set it up as the |
| replacement register if we don't have one for this |
| alternative yet and the operand being replaced is not |
| a cheap CONST_INT. */ |
| if (op_alt_regno[i][j] == -1 |
| && TEST_BIT (preferred, j) |
| && reg_fits_class_p (testreg, rclass, 0, mode) |
| && (!CONST_INT_P (recog_data.operand[i]) |
| || (set_src_cost (recog_data.operand[i], mode, |
| optimize_bb_for_speed_p |
| (BLOCK_FOR_INSN (insn))) |
| > set_src_cost (testreg, mode, |
| optimize_bb_for_speed_p |
| (BLOCK_FOR_INSN (insn)))))) |
| { |
| alternative_nregs[j]++; |
| op_alt_regno[i][j] = regno; |
| } |
| j++; |
| rclass = NO_REGS; |
| break; |
| } |
| p += CONSTRAINT_LEN (c, p); |
| |
| if (c == '\0') |
| break; |
| } |
| } |
| } |
| |
| /* Record all alternatives which are better or equal to the currently |
| matching one in the alternative_order array. */ |
| for (i = j = 0; i < recog_data.n_alternatives; i++) |
| if (alternative_reject[i] <= alternative_reject[which_alternative]) |
| alternative_order[j++] = i; |
| recog_data.n_alternatives = j; |
| |
| /* Sort it. Given a small number of alternatives, a dumb algorithm |
| won't hurt too much. */ |
| for (i = 0; i < recog_data.n_alternatives - 1; i++) |
| { |
| int best = i; |
| int best_reject = alternative_reject[alternative_order[i]]; |
| int best_nregs = alternative_nregs[alternative_order[i]]; |
| |
| for (j = i + 1; j < recog_data.n_alternatives; j++) |
| { |
| int this_reject = alternative_reject[alternative_order[j]]; |
| int this_nregs = alternative_nregs[alternative_order[j]]; |
| |
| if (this_reject < best_reject |
| || (this_reject == best_reject && this_nregs > best_nregs)) |
| { |
| best = j; |
| best_reject = this_reject; |
| best_nregs = this_nregs; |
| } |
| } |
| |
| std::swap (alternative_order[best], alternative_order[i]); |
| } |
| |
| /* Substitute the operands as determined by op_alt_regno for the best |
| alternative. */ |
| j = alternative_order[0]; |
| |
| for (i = 0; i < recog_data.n_operands; i++) |
| { |
| machine_mode mode = recog_data.operand_mode[i]; |
| if (op_alt_regno[i][j] == -1) |
| continue; |
| |
| validate_change (insn, recog_data.operand_loc[i], |
| gen_rtx_REG (mode, op_alt_regno[i][j]), 1); |
| } |
| |
| for (i = recog_data.n_dups - 1; i >= 0; i--) |
| { |
| int op = recog_data.dup_num[i]; |
| machine_mode mode = recog_data.operand_mode[op]; |
| |
| if (op_alt_regno[op][j] == -1) |
| continue; |
| |
| validate_change (insn, recog_data.dup_loc[i], |
| gen_rtx_REG (mode, op_alt_regno[op][j]), 1); |
| } |
| |
| return apply_change_group (); |
| } |
| |
| /* If reload couldn't use reg+reg+offset addressing, try to use reg+reg |
| addressing now. |
| This code might also be useful when reload gave up on reg+reg addressing |
| because of clashes between the return register and INDEX_REG_CLASS. */ |
| |
| /* The maximum number of uses of a register we can keep track of to |
| replace them with reg+reg addressing. */ |
| #define RELOAD_COMBINE_MAX_USES 16 |
| |
| /* Describes a recorded use of a register. */ |
| struct reg_use |
| { |
| /* The insn where a register has been used. */ |
| rtx_insn *insn; |
| /* Points to the memory reference enclosing the use, if any, NULL_RTX |
| otherwise. */ |
| rtx containing_mem; |
| /* Location of the register within INSN. */ |
| rtx *usep; |
| /* The reverse uid of the insn. */ |
| int ruid; |
| }; |
| |
| /* If the register is used in some unknown fashion, USE_INDEX is negative. |
| If it is dead, USE_INDEX is RELOAD_COMBINE_MAX_USES, and STORE_RUID |
| indicates where it is first set or clobbered. |
| Otherwise, USE_INDEX is the index of the last encountered use of the |
| register (which is first among these we have seen since we scan backwards). |
| USE_RUID indicates the first encountered, i.e. last, of these uses. |
| If ALL_OFFSETS_MATCH is true, all encountered uses were inside a PLUS |
| with a constant offset; OFFSET contains this constant in that case. |
| STORE_RUID is always meaningful if we only want to use a value in a |
| register in a different place: it denotes the next insn in the insn |
| stream (i.e. the last encountered) that sets or clobbers the register. |
| REAL_STORE_RUID is similar, but clobbers are ignored when updating it. */ |
| static struct |
| { |
| struct reg_use reg_use[RELOAD_COMBINE_MAX_USES]; |
| rtx offset; |
| int use_index; |
| int store_ruid; |
| int real_store_ruid; |
| int use_ruid; |
| bool all_offsets_match; |
| } reg_state[FIRST_PSEUDO_REGISTER]; |
| |
| /* Reverse linear uid. This is increased in reload_combine while scanning |
| the instructions from last to first. It is used to set last_label_ruid |
| and the store_ruid / use_ruid fields in reg_state. */ |
| static int reload_combine_ruid; |
| |
| /* The RUID of the last label we encountered in reload_combine. */ |
| static int last_label_ruid; |
| |
| /* The RUID of the last jump we encountered in reload_combine. */ |
| static int last_jump_ruid; |
| |
| /* The register numbers of the first and last index register. A value of |
| -1 in LAST_INDEX_REG indicates that we've previously computed these |
| values and found no suitable index registers. */ |
| static int first_index_reg = -1; |
| static int last_index_reg; |
| |
| #define LABEL_LIVE(LABEL) \ |
| (label_live[CODE_LABEL_NUMBER (LABEL) - min_labelno]) |
| |
| /* Subroutine of reload_combine_split_ruids, called to fix up a single |
| ruid pointed to by *PRUID if it is higher than SPLIT_RUID. */ |
| |
| static inline void |
| reload_combine_split_one_ruid (int *pruid, int split_ruid) |
| { |
| if (*pruid > split_ruid) |
| (*pruid)++; |
| } |
| |
| /* Called when we insert a new insn in a position we've already passed in |
| the scan. Examine all our state, increasing all ruids that are higher |
| than SPLIT_RUID by one in order to make room for a new insn. */ |
| |
| static void |
| reload_combine_split_ruids (int split_ruid) |
| { |
| unsigned i; |
| |
| reload_combine_split_one_ruid (&reload_combine_ruid, split_ruid); |
| reload_combine_split_one_ruid (&last_label_ruid, split_ruid); |
| reload_combine_split_one_ruid (&last_jump_ruid, split_ruid); |
| |
| for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
| { |
| int j, idx = reg_state[i].use_index; |
| reload_combine_split_one_ruid (®_state[i].use_ruid, split_ruid); |
| reload_combine_split_one_ruid (®_state[i].store_ruid, split_ruid); |
| reload_combine_split_one_ruid (®_state[i].real_store_ruid, |
| split_ruid); |
| if (idx < 0) |
| continue; |
| for (j = idx; j < RELOAD_COMBINE_MAX_USES; j++) |
| { |
| reload_combine_split_one_ruid (®_state[i].reg_use[j].ruid, |
| split_ruid); |
| } |
| } |
| } |
| |
| /* Called when we are about to rescan a previously encountered insn with |
| reload_combine_note_use after modifying some part of it. This clears all |
| information about uses in that particular insn. */ |
| |
| static void |
| reload_combine_purge_insn_uses (rtx_insn *insn) |
| { |
| unsigned i; |
| |
| for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
| { |
| int j, k, idx = reg_state[i].use_index; |
| if (idx < 0) |
| continue; |
| j = k = RELOAD_COMBINE_MAX_USES; |
| while (j-- > idx) |
| { |
| if (reg_state[i].reg_use[j].insn != insn) |
| { |
| k--; |
| if (k != j) |
| reg_state[i].reg_use[k] = reg_state[i].reg_use[j]; |
| } |
| } |
| reg_state[i].use_index = k; |
| } |
| } |
| |
| /* Called when we need to forget about all uses of REGNO after an insn |
| which is identified by RUID. */ |
| |
| static void |
| reload_combine_purge_reg_uses_after_ruid (unsigned regno, int ruid) |
| { |
| int j, k, idx = reg_state[regno].use_index; |
| if (idx < 0) |
| return; |
| j = k = RELOAD_COMBINE_MAX_USES; |
| while (j-- > idx) |
| { |
| if (reg_state[regno].reg_use[j].ruid >= ruid) |
| { |
| k--; |
| if (k != j) |
| reg_state[regno].reg_use[k] = reg_state[regno].reg_use[j]; |
| } |
| } |
| reg_state[regno].use_index = k; |
| } |
| |
| /* Find the use of REGNO with the ruid that is highest among those |
| lower than RUID_LIMIT, and return it if it is the only use of this |
| reg in the insn. Return NULL otherwise. */ |
| |
| static struct reg_use * |
| reload_combine_closest_single_use (unsigned regno, int ruid_limit) |
| { |
| int i, best_ruid = 0; |
| int use_idx = reg_state[regno].use_index; |
| struct reg_use *retval; |
| |
| if (use_idx < 0) |
| return NULL; |
| retval = NULL; |
| for (i = use_idx; i < RELOAD_COMBINE_MAX_USES; i++) |
| { |
| struct reg_use *use = reg_state[regno].reg_use + i; |
| int this_ruid = use->ruid; |
| if (this_ruid >= ruid_limit) |
| continue; |
| if (this_ruid > best_ruid) |
| { |
| best_ruid = this_ruid; |
| retval = use; |
| } |
| else if (this_ruid == best_ruid) |
| retval = NULL; |
| } |
| if (last_label_ruid >= best_ruid) |
| return NULL; |
| return retval; |
| } |
| |
| /* After we've moved an add insn, fix up any debug insns that occur |
| between the old location of the add and the new location. REG is |
| the destination register of the add insn; REPLACEMENT is the |
| SET_SRC of the add. FROM and TO specify the range in which we |
| should make this change on debug insns. */ |
| |
| static void |
| fixup_debug_insns (rtx reg, rtx replacement, rtx_insn *from, rtx_insn *to) |
| { |
| rtx_insn *insn; |
| for (insn = from; insn != to; insn = NEXT_INSN (insn)) |
| { |
| rtx t; |
| |
| if (!DEBUG_INSN_P (insn)) |
| continue; |
| |
| t = INSN_VAR_LOCATION_LOC (insn); |
| t = simplify_replace_rtx (t, reg, replacement); |
| validate_change (insn, &INSN_VAR_LOCATION_LOC (insn), t, 0); |
| } |
| } |
| |
| /* Subroutine of reload_combine_recognize_const_pattern. Try to replace REG |
| with SRC in the insn described by USE, taking costs into account. Return |
| true if we made the replacement. */ |
| |
| static bool |
| try_replace_in_use (struct reg_use *use, rtx reg, rtx src) |
| { |
| rtx_insn *use_insn = use->insn; |
| rtx mem = use->containing_mem; |
| bool speed = optimize_bb_for_speed_p (BLOCK_FOR_INSN (use_insn)); |
| |
| if (mem != NULL_RTX) |
| { |
| addr_space_t as = MEM_ADDR_SPACE (mem); |
| rtx oldaddr = XEXP (mem, 0); |
| rtx newaddr = NULL_RTX; |
| int old_cost = address_cost (oldaddr, GET_MODE (mem), as, speed); |
| int new_cost; |
| |
| newaddr = simplify_replace_rtx (oldaddr, reg, src); |
| if (memory_address_addr_space_p (GET_MODE (mem), newaddr, as)) |
| { |
| XEXP (mem, 0) = newaddr; |
| new_cost = address_cost (newaddr, GET_MODE (mem), as, speed); |
| XEXP (mem, 0) = oldaddr; |
| if (new_cost <= old_cost |
| && validate_change (use_insn, |
| &XEXP (mem, 0), newaddr, 0)) |
| return true; |
| } |
| } |
| else |
| { |
| rtx new_set = single_set (use_insn); |
| if (new_set |
| && REG_P (SET_DEST (new_set)) |
| && GET_CODE (SET_SRC (new_set)) == PLUS |
| && REG_P (XEXP (SET_SRC (new_set), 0)) |
| && CONSTANT_P (XEXP (SET_SRC (new_set), 1))) |
| { |
| rtx new_src; |
| machine_mode mode = GET_MODE (SET_DEST (new_set)); |
| int old_cost = set_src_cost (SET_SRC (new_set), mode, speed); |
| |
| gcc_assert (rtx_equal_p (XEXP (SET_SRC (new_set), 0), reg)); |
| new_src = simplify_replace_rtx (SET_SRC (new_set), reg, src); |
| |
| if (set_src_cost (new_src, mode, speed) <= old_cost |
| && validate_change (use_insn, &SET_SRC (new_set), |
| new_src, 0)) |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /* Called by reload_combine when scanning INSN. This function tries to detect |
| patterns where a constant is added to a register, and the result is used |
| in an address. |
| Return true if no further processing is needed on INSN; false if it wasn't |
| recognized and should be handled normally. */ |
| |
| static bool |
| reload_combine_recognize_const_pattern (rtx_insn *insn) |
| { |
| int from_ruid = reload_combine_ruid; |
| rtx set, pat, reg, src, addreg; |
| unsigned int regno; |
| struct reg_use *use; |
| bool must_move_add; |
| rtx_insn *add_moved_after_insn = NULL; |
| int add_moved_after_ruid = 0; |
| int clobbered_regno = -1; |
| |
| set = single_set (insn); |
| if (set == NULL_RTX) |
| return false; |
| |
| reg = SET_DEST (set); |
| src = SET_SRC (set); |
| if (!REG_P (reg) |
| || REG_NREGS (reg) != 1 |
| || GET_MODE (reg) != Pmode |
| || reg == stack_pointer_rtx) |
| return false; |
| |
| regno = REGNO (reg); |
| |
| /* We look for a REG1 = REG2 + CONSTANT insn, followed by either |
| uses of REG1 inside an address, or inside another add insn. If |
| possible and profitable, merge the addition into subsequent |
| uses. */ |
| if (GET_CODE (src) != PLUS |
| || !REG_P (XEXP (src, 0)) |
| || !CONSTANT_P (XEXP (src, 1))) |
| return false; |
| |
| addreg = XEXP (src, 0); |
| must_move_add = rtx_equal_p (reg, addreg); |
| |
| pat = PATTERN (insn); |
| if (must_move_add && set != pat) |
| { |
| /* We have to be careful when moving the add; apart from the |
| single_set there may also be clobbers. Recognize one special |
| case, that of one clobber alongside the set (likely a clobber |
| of the CC register). */ |
| gcc_assert (GET_CODE (PATTERN (insn)) == PARALLEL); |
| if (XVECLEN (pat, 0) != 2 || XVECEXP (pat, 0, 0) != set |
| || GET_CODE (XVECEXP (pat, 0, 1)) != CLOBBER |
| || !REG_P (XEXP (XVECEXP (pat, 0, 1), 0))) |
| return false; |
| clobbered_regno = REGNO (XEXP (XVECEXP (pat, 0, 1), 0)); |
| } |
| |
| do |
| { |
| use = reload_combine_closest_single_use (regno, from_ruid); |
| |
| if (use) |
| /* Start the search for the next use from here. */ |
| from_ruid = use->ruid; |
| |
| if (use && GET_MODE (*use->usep) == Pmode) |
| { |
| bool delete_add = false; |
| rtx_insn *use_insn = use->insn; |
| int use_ruid = use->ruid; |
| |
| /* Avoid moving the add insn past a jump. */ |
| if (must_move_add && use_ruid <= last_jump_ruid) |
| break; |
| |
| /* If the add clobbers another hard reg in parallel, don't move |
| it past a real set of this hard reg. */ |
| if (must_move_add && clobbered_regno >= 0 |
| && reg_state[clobbered_regno].real_store_ruid >= use_ruid) |
| break; |
| |
| /* Do not separate cc0 setter and cc0 user on HAVE_cc0 targets. */ |
| if (HAVE_cc0 && must_move_add && sets_cc0_p (PATTERN (use_insn))) |
| break; |
| |
| gcc_assert (reg_state[regno].store_ruid <= use_ruid); |
| /* Avoid moving a use of ADDREG past a point where it is stored. */ |
| if (reg_state[REGNO (addreg)].store_ruid > use_ruid) |
| break; |
| |
| /* We also must not move the addition past an insn that sets |
| the same register, unless we can combine two add insns. */ |
| if (must_move_add && reg_state[regno].store_ruid == use_ruid) |
| { |
| if (use->containing_mem == NULL_RTX) |
| delete_add = true; |
| else |
| break; |
| } |
| |
| if (try_replace_in_use (use, reg, src)) |
| { |
| reload_combine_purge_insn_uses (use_insn); |
| reload_combine_note_use (&PATTERN (use_insn), use_insn, |
| use_ruid, NULL_RTX); |
| |
| if (delete_add) |
| { |
| fixup_debug_insns (reg, src, insn, use_insn); |
| delete_insn (insn); |
| return true; |
| } |
| if (must_move_add) |
| { |
| add_moved_after_insn = use_insn; |
| add_moved_after_ruid = use_ruid; |
| } |
| continue; |
| } |
| } |
| /* If we get here, we couldn't handle this use. */ |
| if (must_move_add) |
| break; |
| } |
| while (use); |
| |
| if (!must_move_add || add_moved_after_insn == NULL_RTX) |
| /* Process the add normally. */ |
| return false; |
| |
| fixup_debug_insns (reg, src, insn, add_moved_after_insn); |
| |
| reorder_insns (insn, insn, add_moved_after_insn); |
| reload_combine_purge_reg_uses_after_ruid (regno, add_moved_after_ruid); |
| reload_combine_split_ruids (add_moved_after_ruid - 1); |
| reload_combine_note_use (&PATTERN (insn), insn, |
| add_moved_after_ruid, NULL_RTX); |
| reg_state[regno].store_ruid = add_moved_after_ruid; |
| |
| return true; |
| } |
| |
| /* Called by reload_combine when scanning INSN. Try to detect a pattern we |
| can handle and improve. Return true if no further processing is needed on |
| INSN; false if it wasn't recognized and should be handled normally. */ |
| |
| static bool |
| reload_combine_recognize_pattern (rtx_insn *insn) |
| { |
| rtx set, reg, src; |
| |
| set = single_set (insn); |
| if (set == NULL_RTX) |
| return false; |
| |
| reg = SET_DEST (set); |
| src = SET_SRC (set); |
| if (!REG_P (reg) || REG_NREGS (reg) != 1) |
| return false; |
| |
| unsigned int regno = REGNO (reg); |
| machine_mode mode = GET_MODE (reg); |
| |
| if (reg_state[regno].use_index < 0 |
| || reg_state[regno].use_index >= RELOAD_COMBINE_MAX_USES) |
| return false; |
| |
| for (int i = reg_state[regno].use_index; |
| i < RELOAD_COMBINE_MAX_USES; i++) |
| { |
| struct reg_use *use = reg_state[regno].reg_use + i; |
| if (GET_MODE (*use->usep) != mode) |
| return false; |
| } |
| |
| /* Look for (set (REGX) (CONST_INT)) |
| (set (REGX) (PLUS (REGX) (REGY))) |
| ... |
| ... (MEM (REGX)) ... |
| and convert it to |
| (set (REGZ) (CONST_INT)) |
| ... |
| ... (MEM (PLUS (REGZ) (REGY)))... . |
| |
| First, check that we have (set (REGX) (PLUS (REGX) (REGY))) |
| and that we know all uses of REGX before it dies. |
| Also, explicitly check that REGX != REGY; our life information |
| does not yet show whether REGY changes in this insn. */ |
| |
| if (GET_CODE (src) == PLUS |
| && reg_state[regno].all_offsets_match |
| && last_index_reg != -1 |
| && REG_P (XEXP (src, 1)) |
| && rtx_equal_p (XEXP (src, 0), reg) |
| && !rtx_equal_p (XEXP (src, 1), reg) |
| && last_label_ruid < reg_state[regno].use_ruid) |
| { |
| rtx base = XEXP (src, 1); |
| rtx_insn *prev = prev_nonnote_nondebug_insn (insn); |
| rtx prev_set = prev ? single_set (prev) : NULL_RTX; |
| rtx index_reg = NULL_RTX; |
| rtx reg_sum = NULL_RTX; |
| int i; |
| |
| /* Now we need to set INDEX_REG to an index register (denoted as |
| REGZ in the illustration above) and REG_SUM to the expression |
| register+register that we want to use to substitute uses of REG |
| (typically in MEMs) with. First check REG and BASE for being |
| index registers; we can use them even if they are not dead. */ |
| if (TEST_HARD_REG_BIT (reg_class_contents[INDEX_REG_CLASS], regno) |
| || TEST_HARD_REG_BIT (reg_class_contents[INDEX_REG_CLASS], |
| REGNO (base))) |
| { |
| index_reg = reg; |
| reg_sum = src; |
| } |
| else |
| { |
| /* Otherwise, look for a free index register. Since we have |
| checked above that neither REG nor BASE are index registers, |
| if we find anything at all, it will be different from these |
| two registers. */ |
| for (i = first_index_reg; i <= last_index_reg; i++) |
| { |
| if (TEST_HARD_REG_BIT (reg_class_contents[INDEX_REG_CLASS], i) |
| && reg_state[i].use_index == RELOAD_COMBINE_MAX_USES |
| && reg_state[i].store_ruid <= reg_state[regno].use_ruid |
| && (call_used_regs[i] || df_regs_ever_live_p (i)) |
| && (!frame_pointer_needed || i != HARD_FRAME_POINTER_REGNUM) |
| && !fixed_regs[i] && !global_regs[i] |
| && hard_regno_nregs (i, GET_MODE (reg)) == 1 |
| && targetm.hard_regno_scratch_ok (i)) |
| { |
| index_reg = gen_rtx_REG (GET_MODE (reg), i); |
| reg_sum = gen_rtx_PLUS (GET_MODE (reg), index_reg, base); |
| break; |
| } |
| } |
| } |
| |
| /* Check that PREV_SET is indeed (set (REGX) (CONST_INT)) and that |
| (REGY), i.e. BASE, is not clobbered before the last use we'll |
| create. */ |
| if (reg_sum |
| && prev_set |
| && CONST_INT_P (SET_SRC (prev_set)) |
| && rtx_equal_p (SET_DEST (prev_set), reg) |
| && (reg_state[REGNO (base)].store_ruid |
| <= reg_state[regno].use_ruid)) |
| { |
| /* Change destination register and, if necessary, the constant |
| value in PREV, the constant loading instruction. */ |
| validate_change (prev, &SET_DEST (prev_set), index_reg, 1); |
| if (reg_state[regno].offset != const0_rtx) |
| validate_change (prev, |
| &SET_SRC (prev_set), |
| GEN_INT (INTVAL (SET_SRC (prev_set)) |
| + INTVAL (reg_state[regno].offset)), |
| 1); |
| |
| /* Now for every use of REG that we have recorded, replace REG |
| with REG_SUM. */ |
| for (i = reg_state[regno].use_index; |
| i < RELOAD_COMBINE_MAX_USES; i++) |
| validate_unshare_change (reg_state[regno].reg_use[i].insn, |
| reg_state[regno].reg_use[i].usep, |
| /* Each change must have its own |
| replacement. */ |
| reg_sum, 1); |
| |
| if (apply_change_group ()) |
| { |
| struct reg_use *lowest_ruid = NULL; |
| |
| /* For every new use of REG_SUM, we have to record the use |
| of BASE therein, i.e. operand 1. */ |
| for (i = reg_state[regno].use_index; |
| i < RELOAD_COMBINE_MAX_USES; i++) |
| { |
| struct reg_use *use = reg_state[regno].reg_use + i; |
| reload_combine_note_use (&XEXP (*use->usep, 1), use->insn, |
| use->ruid, use->containing_mem); |
| if (lowest_ruid == NULL || use->ruid < lowest_ruid->ruid) |
| lowest_ruid = use; |
| } |
| |
| fixup_debug_insns (reg, reg_sum, insn, lowest_ruid->insn); |
| |
| /* Delete the reg-reg addition. */ |
| delete_insn (insn); |
| |
| if (reg_state[regno].offset != const0_rtx |
| /* Previous REG_EQUIV / REG_EQUAL notes for PREV |
| are now invalid. */ |
| && remove_reg_equal_equiv_notes (prev)) |
| df_notes_rescan (prev); |
| |
| reg_state[regno].use_index = RELOAD_COMBINE_MAX_USES; |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| |
| static void |
| reload_combine (void) |
| { |
| rtx_insn *insn, *prev; |
| basic_block bb; |
| unsigned int r; |
| int min_labelno, n_labels; |
| HARD_REG_SET ever_live_at_start, *label_live; |
| |
| /* To avoid wasting too much time later searching for an index register, |
| determine the minimum and maximum index register numbers. */ |
| if (INDEX_REG_CLASS == NO_REGS) |
| last_index_reg = -1; |
| else if (first_index_reg == -1 && last_index_reg == 0) |
| { |
| for (r = 0; r < FIRST_PSEUDO_REGISTER; r++) |
| if (TEST_HARD_REG_BIT (reg_class_contents[INDEX_REG_CLASS], r)) |
| { |
| if (first_index_reg == -1) |
| first_index_reg = r; |
| |
| last_index_reg = r; |
| } |
| |
| /* If no index register is available, we can quit now. Set LAST_INDEX_REG |
| to -1 so we'll know to quit early the next time we get here. */ |
| if (first_index_reg == -1) |
| { |
| last_index_reg = -1; |
| return; |
| } |
| } |
| |
| /* Set up LABEL_LIVE and EVER_LIVE_AT_START. The register lifetime |
| information is a bit fuzzy immediately after reload, but it's |
| still good enough to determine which registers are live at a jump |
| destination. */ |
| min_labelno = get_first_label_num (); |
| n_labels = max_label_num () - min_labelno; |
| label_live = XNEWVEC (HARD_REG_SET, n_labels); |
| CLEAR_HARD_REG_SET (ever_live_at_start); |
| |
| FOR_EACH_BB_REVERSE_FN (bb, cfun) |
| { |
| insn = BB_HEAD (bb); |
| if (LABEL_P (insn)) |
| { |
| HARD_REG_SET live; |
| bitmap live_in = df_get_live_in (bb); |
| |
| REG_SET_TO_HARD_REG_SET (live, live_in); |
| compute_use_by_pseudos (&live, live_in); |
| COPY_HARD_REG_SET (LABEL_LIVE (insn), live); |
| IOR_HARD_REG_SET (ever_live_at_start, live); |
| } |
| } |
| |
| /* Initialize last_label_ruid, reload_combine_ruid and reg_state. */ |
| last_label_ruid = last_jump_ruid = reload_combine_ruid = 0; |
| for (r = 0; r < FIRST_PSEUDO_REGISTER; r++) |
| { |
| reg_state[r].store_ruid = 0; |
| reg_state[r].real_store_ruid = 0; |
| if (fixed_regs[r]) |
| reg_state[r].use_index = -1; |
| else |
| reg_state[r].use_index = RELOAD_COMBINE_MAX_USES; |
| } |
| |
| for (insn = get_last_insn (); insn; insn = prev) |
| { |
| bool control_flow_insn; |
| rtx note; |
| |
| prev = PREV_INSN (insn); |
| |
| /* We cannot do our optimization across labels. Invalidating all the use |
| information we have would be costly, so we just note where the label |
| is and then later disable any optimization that would cross it. */ |
| if (LABEL_P (insn)) |
| last_label_ruid = reload_combine_ruid; |
| else if (BARRIER_P (insn)) |
| { |
| /* Crossing a barrier resets all the use information. */ |
| for (r = 0; r < FIRST_PSEUDO_REGISTER; r++) |
| if (! fixed_regs[r]) |
| reg_state[r].use_index = RELOAD_COMBINE_MAX_USES; |
| } |
| else if (INSN_P (insn) && volatile_insn_p (PATTERN (insn))) |
| /* Optimizations across insns being marked as volatile must be |
| prevented. All the usage information is invalidated |
| here. */ |
| for (r = 0; r < FIRST_PSEUDO_REGISTER; r++) |
| if (! fixed_regs[r] |
| && reg_state[r].use_index != RELOAD_COMBINE_MAX_USES) |
| reg_state[r].use_index = -1; |
| |
| if (! NONDEBUG_INSN_P (insn)) |
| continue; |
| |
| reload_combine_ruid++; |
| |
| control_flow_insn = control_flow_insn_p (insn); |
| if (control_flow_insn) |
| last_jump_ruid = reload_combine_ruid; |
| |
| if (reload_combine_recognize_const_pattern (insn) |
| || reload_combine_recognize_pattern (insn)) |
| continue; |
| |
| note_stores (PATTERN (insn), reload_combine_note_store, NULL); |
| |
| if (CALL_P (insn)) |
| { |
| rtx link; |
| HARD_REG_SET used_regs; |
| |
| get_call_reg_set_usage (insn, &used_regs, call_used_reg_set); |
| |
| for (r = 0; r < FIRST_PSEUDO_REGISTER; r++) |
| if (TEST_HARD_REG_BIT (used_regs, r)) |
| { |
| reg_state[r].use_index = RELOAD_COMBINE_MAX_USES; |
| reg_state[r].store_ruid = reload_combine_ruid; |
| } |
| |
| for (link = CALL_INSN_FUNCTION_USAGE (insn); link; |
| link = XEXP (link, 1)) |
| { |
| rtx setuse = XEXP (link, 0); |
| rtx usage_rtx = XEXP (setuse, 0); |
| if ((GET_CODE (setuse) == USE || GET_CODE (setuse) == CLOBBER) |
| && REG_P (usage_rtx)) |
| { |
| unsigned int end_regno = END_REGNO (usage_rtx); |
| for (unsigned int i = REGNO (usage_rtx); i < end_regno; ++i) |
| if (GET_CODE (XEXP (link, 0)) == CLOBBER) |
| { |
| reg_state[i].use_index = RELOAD_COMBINE_MAX_USES; |
| reg_state[i].store_ruid = reload_combine_ruid; |
| } |
| else |
| reg_state[i].use_index = -1; |
| } |
| } |
| } |
| |
| if (control_flow_insn && !ANY_RETURN_P (PATTERN (insn))) |
| { |
| /* Non-spill registers might be used at the call destination in |
| some unknown fashion, so we have to mark the unknown use. */ |
| HARD_REG_SET *live; |
| |
| if ((condjump_p (insn) || condjump_in_parallel_p (insn)) |
| && JUMP_LABEL (insn)) |
| { |
| if (ANY_RETURN_P (JUMP_LABEL (insn))) |
| live = NULL; |
| else |
| live = &LABEL_LIVE (JUMP_LABEL (insn)); |
| } |
| else |
| live = &ever_live_at_start; |
| |
| if (live) |
| for (r = 0; r < FIRST_PSEUDO_REGISTER; r++) |
| if (TEST_HARD_REG_BIT (*live, r)) |
| reg_state[r].use_index = -1; |
| } |
| |
| reload_combine_note_use (&PATTERN (insn), insn, reload_combine_ruid, |
| NULL_RTX); |
| |
| for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) |
| { |
| if (REG_NOTE_KIND (note) == REG_INC && REG_P (XEXP (note, 0))) |
| { |
| int regno = REGNO (XEXP (note, 0)); |
| reg_state[regno].store_ruid = reload_combine_ruid; |
| reg_state[regno].real_store_ruid = reload_combine_ruid; |
| reg_state[regno].use_index = -1; |
| } |
| } |
| } |
| |
| free (label_live); |
| } |
| |
| /* Check if DST is a register or a subreg of a register; if it is, |
| update store_ruid, real_store_ruid and use_index in the reg_state |
| structure accordingly. Called via note_stores from reload_combine. */ |
| |
| static void |
| reload_combine_note_store (rtx dst, const_rtx set, void *data ATTRIBUTE_UNUSED) |
| { |
| int regno = 0; |
| int i; |
| machine_mode mode = GET_MODE (dst); |
| |
| if (GET_CODE (dst) == SUBREG) |
| { |
| regno = subreg_regno_offset (REGNO (SUBREG_REG (dst)), |
| GET_MODE (SUBREG_REG (dst)), |
| SUBREG_BYTE (dst), |
| GET_MODE (dst)); |
| dst = SUBREG_REG (dst); |
| } |
| |
| /* Some targets do argument pushes without adding REG_INC notes. */ |
| |
| if (MEM_P (dst)) |
| { |
| dst = XEXP (dst, 0); |
| if (GET_CODE (dst) == PRE_INC || GET_CODE (dst) == POST_INC |
| || GET_CODE (dst) == PRE_DEC || GET_CODE (dst) == POST_DEC |
| || GET_CODE (dst) == PRE_MODIFY || GET_CODE (dst) == POST_MODIFY) |
| { |
| unsigned int end_regno = END_REGNO (XEXP (dst, 0)); |
| for (unsigned int i = REGNO (XEXP (dst, 0)); i < end_regno; ++i) |
| { |
| /* We could probably do better, but for now mark the register |
| as used in an unknown fashion and set/clobbered at this |
| insn. */ |
| reg_state[i].use_index = -1; |
| reg_state[i].store_ruid = reload_combine_ruid; |
| reg_state[i].real_store_ruid = reload_combine_ruid; |
| } |
| } |
| else |
| return; |
| } |
| |
| if (!REG_P (dst)) |
| return; |
| regno += REGNO (dst); |
| |
| /* note_stores might have stripped a STRICT_LOW_PART, so we have to be |
| careful with registers / register parts that are not full words. |
| Similarly for ZERO_EXTRACT. */ |
| if (GET_CODE (SET_DEST (set)) == ZERO_EXTRACT |
| || GET_CODE (SET_DEST (set)) == STRICT_LOW_PART) |
| { |
| for (i = end_hard_regno (mode, regno) - 1; i >= regno; i--) |
| { |
| reg_state[i].use_index = -1; |
| reg_state[i].store_ruid = reload_combine_ruid; |
| reg_state[i].real_store_ruid = reload_combine_ruid; |
| } |
| } |
| else |
| { |
| for (i = end_hard_regno (mode, regno) - 1; i >= regno; i--) |
| { |
| reg_state[i].store_ruid = reload_combine_ruid; |
| if (GET_CODE (set) == SET) |
| reg_state[i].real_store_ruid = reload_combine_ruid; |
| reg_state[i].use_index = RELOAD_COMBINE_MAX_USES; |
| } |
| } |
| } |
| |
| /* XP points to a piece of rtl that has to be checked for any uses of |
| registers. |
| *XP is the pattern of INSN, or a part of it. |
| Called from reload_combine, and recursively by itself. */ |
| static void |
| reload_combine_note_use (rtx *xp, rtx_insn *insn, int ruid, rtx containing_mem) |
| { |
| rtx x = *xp; |
| enum rtx_code code = x->code; |
| const char *fmt; |
| int i, j; |
| rtx offset = const0_rtx; /* For the REG case below. */ |
| |
| switch (code) |
| { |
| case SET: |
| if (REG_P (SET_DEST (x))) |
| { |
| reload_combine_note_use (&SET_SRC (x), insn, ruid, NULL_RTX); |
| return; |
| } |
| break; |
| |
| case USE: |
| /* If this is the USE of a return value, we can't change it. */ |
| if (REG_P (XEXP (x, 0)) && REG_FUNCTION_VALUE_P (XEXP (x, 0))) |
| { |
| /* Mark the return register as used in an unknown fashion. */ |
| rtx reg = XEXP (x, 0); |
| unsigned int end_regno = END_REGNO (reg); |
| for (unsigned int regno = REGNO (reg); regno < end_regno; ++regno) |
| reg_state[regno].use_index = -1; |
| return; |
| } |
| break; |
| |
| case CLOBBER: |
| if (REG_P (SET_DEST (x))) |
| { |
| /* No spurious CLOBBERs of pseudo registers may remain. */ |
| gcc_assert (REGNO (SET_DEST (x)) < FIRST_PSEUDO_REGISTER); |
| return; |
| } |
| break; |
| |
| case PLUS: |
| /* We are interested in (plus (reg) (const_int)) . */ |
| if (!REG_P (XEXP (x, 0)) |
| || !CONST_INT_P (XEXP (x, 1))) |
| break; |
| offset = XEXP (x, 1); |
| x = XEXP (x, 0); |
| /* Fall through. */ |
| case REG: |
| { |
| int regno = REGNO (x); |
| int use_index; |
| int nregs; |
| |
| /* No spurious USEs of pseudo registers may remain. */ |
| gcc_assert (regno < FIRST_PSEUDO_REGISTER); |
| |
| nregs = REG_NREGS (x); |
| |
| /* We can't substitute into multi-hard-reg uses. */ |
| if (nregs > 1) |
| { |
| while (--nregs >= 0) |
| reg_state[regno + nregs].use_index = -1; |
| return; |
| } |
| |
| /* We may be called to update uses in previously seen insns. |
| Don't add uses beyond the last store we saw. */ |
| if (ruid < reg_state[regno].store_ruid) |
| return; |
| |
| /* If this register is already used in some unknown fashion, we |
| can't do anything. |
| If we decrement the index from zero to -1, we can't store more |
| uses, so this register becomes used in an unknown fashion. */ |
| use_index = --reg_state[regno].use_index; |
| if (use_index < 0) |
| return; |
| |
| if (use_index == RELOAD_COMBINE_MAX_USES - 1) |
| { |
| /* This is the first use of this register we have seen since we |
| marked it as dead. */ |
| reg_state[regno].offset = offset; |
| reg_state[regno].all_offsets_match = true; |
| reg_state[regno].use_ruid = ruid; |
| } |
| else |
| { |
| if (reg_state[regno].use_ruid > ruid) |
| reg_state[regno].use_ruid = ruid; |
| |
| if (! rtx_equal_p (offset, reg_state[regno].offset)) |
| reg_state[regno].all_offsets_match = false; |
| } |
| |
| reg_state[regno].reg_use[use_index].insn = insn; |
| reg_state[regno].reg_use[use_index].ruid = ruid; |
| reg_state[regno].reg_use[use_index].containing_mem = containing_mem; |
| reg_state[regno].reg_use[use_index].usep = xp; |
| return; |
| } |
| |
| case MEM: |
| containing_mem = x; |
| break; |
| |
| default: |
| break; |
| } |
| |
| /* Recursively process the components of X. */ |
| fmt = GET_RTX_FORMAT (code); |
| for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) |
| { |
| if (fmt[i] == 'e') |
| reload_combine_note_use (&XEXP (x, i), insn, ruid, containing_mem); |
| else if (fmt[i] == 'E') |
| { |
| for (j = XVECLEN (x, i) - 1; j >= 0; j--) |
| reload_combine_note_use (&XVECEXP (x, i, j), insn, ruid, |
| containing_mem); |
| } |
| } |
| } |
| |
| /* See if we can reduce the cost of a constant by replacing a move |
| with an add. We track situations in which a register is set to a |
| constant or to a register plus a constant. */ |
| /* We cannot do our optimization across labels. Invalidating all the |
| information about register contents we have would be costly, so we |
| use move2add_last_label_luid to note where the label is and then |
| later disable any optimization that would cross it. |
| reg_offset[n] / reg_base_reg[n] / reg_symbol_ref[n] / reg_mode[n] |
| are only valid if reg_set_luid[n] is greater than |
| move2add_last_label_luid. |
| For a set that established a new (potential) base register with |
| non-constant value, we use move2add_luid from the place where the |
| setting insn is encountered; registers based off that base then |
| get the same reg_set_luid. Constants all get |
| move2add_last_label_luid + 1 as their reg_set_luid. */ |
| static int reg_set_luid[FIRST_PSEUDO_REGISTER]; |
| |
| /* If reg_base_reg[n] is negative, register n has been set to |
| reg_offset[n] or reg_symbol_ref[n] + reg_offset[n] in mode reg_mode[n]. |
| If reg_base_reg[n] is non-negative, register n has been set to the |
| sum of reg_offset[n] and the value of register reg_base_reg[n] |
| before reg_set_luid[n], calculated in mode reg_mode[n] . |
| For multi-hard-register registers, all but the first one are |
| recorded as BLKmode in reg_mode. Setting reg_mode to VOIDmode |
| marks it as invalid. */ |
| static HOST_WIDE_INT reg_offset[FIRST_PSEUDO_REGISTER]; |
| static int reg_base_reg[FIRST_PSEUDO_REGISTER]; |
| static rtx reg_symbol_ref[FIRST_PSEUDO_REGISTER]; |
| static machine_mode reg_mode[FIRST_PSEUDO_REGISTER]; |
| |
| /* move2add_luid is linearly increased while scanning the instructions |
| from first to last. It is used to set reg_set_luid in |
| reload_cse_move2add and move2add_note_store. */ |
| static int move2add_luid; |
| |
| /* move2add_last_label_luid is set whenever a label is found. Labels |
| invalidate all previously collected reg_offset data. */ |
| static int move2add_last_label_luid; |
| |
| /* ??? We don't know how zero / sign extension is handled, hence we |
| can't go from a narrower to a wider mode. */ |
| #define MODES_OK_FOR_MOVE2ADD(OUTMODE, INMODE) \ |
| (GET_MODE_SIZE (OUTMODE) == GET_MODE_SIZE (INMODE) \ |
| || (GET_MODE_SIZE (OUTMODE) <= GET_MODE_SIZE (INMODE) \ |
| && TRULY_NOOP_TRUNCATION_MODES_P (OUTMODE, INMODE))) |
| |
| /* Record that REG is being set to a value with the mode of REG. */ |
| |
| static void |
| move2add_record_mode (rtx reg) |
| { |
| int regno, nregs; |
| machine_mode mode = GET_MODE (reg); |
| |
| if (GET_CODE (reg) == SUBREG) |
| { |
| regno = subreg_regno (reg); |
| nregs = subreg_nregs (reg); |
| } |
| else if (REG_P (reg)) |
| { |
| regno = REGNO (reg); |
| nregs = REG_NREGS (reg); |
| } |
| else |
| gcc_unreachable (); |
| for (int i = nregs - 1; i > 0; i--) |
| reg_mode[regno + i] = BLKmode; |
| reg_mode[regno] = mode; |
| } |
| |
| /* Record that REG is being set to the sum of SYM and OFF. */ |
| |
| static void |
| move2add_record_sym_value (rtx reg, rtx sym, rtx off) |
| { |
| int regno = REGNO (reg); |
| |
| move2add_record_mode (reg); |
| reg_set_luid[regno] = move2add_luid; |
| reg_base_reg[regno] = -1; |
| reg_symbol_ref[regno] = sym; |
| reg_offset[regno] = INTVAL (off); |
| } |
| |
| /* Check if REGNO contains a valid value in MODE. */ |
| |
| static bool |
| move2add_valid_value_p (int regno, scalar_int_mode mode) |
| { |
| if (reg_set_luid[regno] <= move2add_last_label_luid) |
| return false; |
| |
| if (mode != reg_mode[regno]) |
| { |
| scalar_int_mode old_mode; |
| if (!is_a <scalar_int_mode> (reg_mode[regno], &old_mode) |
| || !MODES_OK_FOR_MOVE2ADD (mode, old_mode)) |
| return false; |
| /* The value loaded into regno in reg_mode[regno] is also valid in |
| mode after truncation only if (REG:mode regno) is the lowpart of |
| (REG:reg_mode[regno] regno). Now, for big endian, the starting |
| regno of the lowpart might be different. */ |
| int s_off = subreg_lowpart_offset (mode, old_mode); |
| s_off = subreg_regno_offset (regno, old_mode, s_off, mode); |
| if (s_off != 0) |
| /* We could in principle adjust regno, check reg_mode[regno] to be |
| BLKmode, and return s_off to the caller (vs. -1 for failure), |
| but we currently have no callers that could make use of this |
| information. */ |
| return false; |
| } |
| |
| for (int i = end_hard_regno (mode, regno) - 1; i > regno; i--) |
| if (reg_mode[i] != BLKmode) |
| return false; |
| return true; |
| } |
| |
| /* This function is called with INSN that sets REG (of mode MODE) |
| to (SYM + OFF), while REG is known to already have value (SYM + offset). |
| This function tries to change INSN into an add instruction |
| (set (REG) (plus (REG) (OFF - offset))) using the known value. |
| It also updates the information about REG's known value. |
| Return true if we made a change. */ |
| |
| static bool |
| move2add_use_add2_insn (scalar_int_mode mode, rtx reg, rtx sym, rtx off, |
| rtx_insn *insn) |
| { |
| rtx pat = PATTERN (insn); |
| rtx src = SET_SRC (pat); |
| int regno = REGNO (reg); |
| rtx new_src = gen_int_mode (UINTVAL (off) - reg_offset[regno], mode); |
| bool speed = optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn)); |
| bool changed = false; |
| |
| /* (set (reg) (plus (reg) (const_int 0))) is not canonical; |
| use (set (reg) (reg)) instead. |
| We don't delete this insn, nor do we convert it into a |
| note, to avoid losing register notes or the return |
| value flag. jump2 already knows how to get rid of |
| no-op moves. */ |
| if (new_src == const0_rtx) |
| { |
| /* If the constants are different, this is a |
| truncation, that, if turned into (set (reg) |
| (reg)), would be discarded. Maybe we should |
| try a truncMN pattern? */ |
| if (INTVAL (off) == reg_offset [regno]) |
| changed = validate_change (insn, &SET_SRC (pat), reg, 0); |
| } |
| else |
| { |
| struct full_rtx_costs oldcst, newcst; |
| rtx tem = gen_rtx_PLUS (mode, reg, new_src); |
| |
| get_full_set_rtx_cost (pat, &oldcst); |
| SET_SRC (pat) = tem; |
| get_full_set_rtx_cost (pat, &newcst); |
| SET_SRC (pat) = src; |
| |
| if (costs_lt_p (&newcst, &oldcst, speed) |
| && have_add2_insn (reg, new_src)) |
| changed = validate_change (insn, &SET_SRC (pat), tem, 0); |
| else if (sym == NULL_RTX && mode != BImode) |
| { |
| scalar_int_mode narrow_mode; |
| FOR_EACH_MODE_UNTIL (narrow_mode, mode) |
| { |
| if (have_insn_for (STRICT_LOW_PART, narrow_mode) |
| && ((reg_offset[regno] & ~GET_MODE_MASK (narrow_mode)) |
| == (INTVAL (off) & ~GET_MODE_MASK (narrow_mode)))) |
| { |
| rtx narrow_reg = gen_lowpart_common (narrow_mode, reg); |
| rtx narrow_src = gen_int_mode (INTVAL (off), |
| narrow_mode); |
| rtx new_set |
| = gen_rtx_SET (gen_rtx_STRICT_LOW_PART (VOIDmode, |
| narrow_reg), |
| narrow_src); |
| get_full_set_rtx_cost (new_set, &newcst); |
| if (costs_lt_p (&newcst, &oldcst, speed)) |
| { |
| changed = validate_change (insn, &PATTERN (insn), |
| new_set, 0); |
| if (changed) |
| break; |
| } |
| } |
| } |
| } |
| } |
| move2add_record_sym_value (reg, sym, off); |
| return changed; |
| } |
| |
| |
| /* This function is called with INSN that sets REG (of mode MODE) to |
| (SYM + OFF), but REG doesn't have known value (SYM + offset). This |
| function tries to find another register which is known to already have |
| value (SYM + offset) and change INSN into an add instruction |
| (set (REG) (plus (the found register) (OFF - offset))) if such |
| a register is found. It also updates the information about |
| REG's known value. |
| Return true iff we made a change. */ |
| |
| static bool |
| move2add_use_add3_insn (scalar_int_mode mode, rtx reg, rtx sym, rtx off, |
| rtx_insn *insn) |
| { |
| rtx pat = PATTERN (insn); |
| rtx src = SET_SRC (pat); |
| int regno = REGNO (reg); |
| int min_regno = 0; |
| bool speed = optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn)); |
| int i; |
| bool changed = false; |
| struct full_rtx_costs oldcst, newcst, mincst; |
| rtx plus_expr; |
| |
| init_costs_to_max (&mincst); |
| get_full_set_rtx_cost (pat, &oldcst); |
| |
| plus_expr = gen_rtx_PLUS (GET_MODE (reg), reg, const0_rtx); |
| SET_SRC (pat) = plus_expr; |
| |
| for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
| if (move2add_valid_value_p (i, mode) |
| && reg_base_reg[i] < 0 |
| && reg_symbol_ref[i] != NULL_RTX |
| && rtx_equal_p (sym, reg_symbol_ref[i])) |
| { |
| rtx new_src = gen_int_mode (UINTVAL (off) - reg_offset[i], |
| GET_MODE (reg)); |
| /* (set (reg) (plus (reg) (const_int 0))) is not canonical; |
| use (set (reg) (reg)) instead. |
| We don't delete this insn, nor do we convert it into a |
| note, to avoid losing register notes or the return |
| value flag. jump2 already knows how to get rid of |
| no-op moves. */ |
| if (new_src == const0_rtx) |
| { |
| init_costs_to_zero (&mincst); |
| min_regno = i; |
| break; |
| } |
| else |
| { |
| XEXP (plus_expr, 1) = new_src; |
| get_full_set_rtx_cost (pat, &newcst); |
| |
| if (costs_lt_p (&newcst, &mincst, speed)) |
| { |
| mincst = newcst; |
| min_regno = i; |
| } |
| } |
| } |
| SET_SRC (pat) = src; |
| |
| if (costs_lt_p (&mincst, &oldcst, speed)) |
| { |
| rtx tem; |
| |
| tem = gen_rtx_REG (GET_MODE (reg), min_regno); |
| if (i != min_regno) |
| { |
| rtx new_src = gen_int_mode (UINTVAL (off) - reg_offset[min_regno], |
| GET_MODE (reg)); |
| tem = gen_rtx_PLUS (GET_MODE (reg), tem, new_src); |
| } |
| if (validate_change (insn, &SET_SRC (pat), tem, 0)) |
| changed = true; |
| } |
| reg_set_luid[regno] = move2add_luid; |
| move2add_record_sym_value (reg, sym, off); |
| return changed; |
| } |
| |
| /* Convert move insns with constant inputs to additions if they are cheaper. |
| Return true if any changes were made. */ |
| static bool |
| reload_cse_move2add (rtx_insn *first) |
| { |
| int i; |
| rtx_insn *insn; |
| bool changed = false; |
| |
| for (i = FIRST_PSEUDO_REGISTER - 1; i >= 0; i--) |
| { |
| reg_set_luid[i] = 0; |
| reg_offset[i] = 0; |
| reg_base_reg[i] = 0; |
| reg_symbol_ref[i] = NULL_RTX; |
| reg_mode[i] = VOIDmode; |
| } |
| |
| move2add_last_label_luid = 0; |
| move2add_luid = 2; |
| for (insn = first; insn; insn = NEXT_INSN (insn), move2add_luid++) |
| { |
| rtx pat, note; |
| |
| if (LABEL_P (insn)) |
| { |
| move2add_last_label_luid = move2add_luid; |
| /* We're going to increment move2add_luid twice after a |
| label, so that we can use move2add_last_label_luid + 1 as |
| the luid for constants. */ |
| move2add_luid++; |
| continue; |
| } |
| if (! INSN_P (insn)) |
| continue; |
| pat = PATTERN (insn); |
| /* For simplicity, we only perform this optimization on |
| straightforward SETs. */ |
| scalar_int_mode mode; |
| if (GET_CODE (pat) == SET |
| && REG_P (SET_DEST (pat)) |
| && is_a <scalar_int_mode> (GET_MODE (SET_DEST (pat)), &mode)) |
| { |
| rtx reg = SET_DEST (pat); |
| int regno = REGNO (reg); |
| rtx src = SET_SRC (pat); |
| |
| /* Check if we have valid information on the contents of this |
| register in the mode of REG. */ |
| if (move2add_valid_value_p (regno, mode) |
| && dbg_cnt (cse2_move2add)) |
| { |
| /* Try to transform (set (REGX) (CONST_INT A)) |
| ... |
| (set (REGX) (CONST_INT B)) |
| to |
| (set (REGX) (CONST_INT A)) |
| ... |
| (set (REGX) (plus (REGX) (CONST_INT B-A))) |
| or |
| (set (REGX) (CONST_INT A)) |
| ... |
| (set (STRICT_LOW_PART (REGX)) (CONST_INT B)) |
| */ |
| |
| if (CONST_INT_P (src) |
| && reg_base_reg[regno] < 0 |
| && reg_symbol_ref[regno] == NULL_RTX) |
| { |
| changed |= move2add_use_add2_insn (mode, reg, NULL_RTX, |
| src, insn); |
| continue; |
| } |
| |
| /* Try to transform (set (REGX) (REGY)) |
| (set (REGX) (PLUS (REGX) (CONST_INT A))) |
| ... |
| (set (REGX) (REGY)) |
| (set (REGX) (PLUS (REGX) (CONST_INT B))) |
| to |
| (set (REGX) (REGY)) |
| (set (REGX) (PLUS (REGX) (CONST_INT A))) |
| ... |
| (set (REGX) (plus (REGX) (CONST_INT B-A))) */ |
| else if (REG_P (src) |
| && reg_set_luid[regno] == reg_set_luid[REGNO (src)] |
| && reg_base_reg[regno] == reg_base_reg[REGNO (src)] |
| && move2add_valid_value_p (REGNO (src), mode)) |
| { |
| rtx_insn *next = next_nonnote_nondebug_insn (insn); |
| rtx set = NULL_RTX; |
| if (next) |
| set = single_set (next); |
| if (set |
| && SET_DEST (set) == reg |
| && GET_CODE (SET_SRC (set)) == PLUS |
| && XEXP (SET_SRC (set), 0) == reg |
| && CONST_INT_P (XEXP (SET_SRC (set), 1))) |
| { |
| rtx src3 = XEXP (SET_SRC (set), 1); |
| unsigned HOST_WIDE_INT added_offset = UINTVAL (src3); |
| HOST_WIDE_INT base_offset = reg_offset[REGNO (src)]; |
| HOST_WIDE_INT regno_offset = reg_offset[regno]; |
| rtx new_src = |
| gen_int_mode (added_offset |
| + base_offset |
| - regno_offset, |
| mode); |
| bool success = false; |
| bool speed = optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn)); |
| |
| if (new_src == const0_rtx) |
| /* See above why we create (set (reg) (reg)) here. */ |
| success |
| = validate_change (next, &SET_SRC (set), reg, 0); |
| else |
| { |
| rtx old_src = SET_SRC (set); |
| struct full_rtx_costs oldcst, newcst; |
| rtx tem = gen_rtx_PLUS (mode, reg, new_src); |
| |
| get_full_set_rtx_cost (set, &oldcst); |
| SET_SRC (set) = tem; |
| get_full_set_src_cost (tem, mode, &newcst); |
| SET_SRC (set) = old_src; |
| costs_add_n_insns (&oldcst, 1); |
| |
| if (costs_lt_p (&newcst, &oldcst, speed) |
| && have_add2_insn (reg, new_src)) |
| { |
| rtx newpat = gen_rtx_SET (reg, tem); |
| success |
| = validate_change (next, &PATTERN (next), |
| newpat, 0); |
| } |
| } |
| if (success) |
| delete_insn (insn); |
| changed |= success; |
| insn = next; |
| move2add_record_mode (reg); |
| reg_offset[regno] |
| = trunc_int_for_mode (added_offset + base_offset, |
| mode); |
| continue; |
| } |
| } |
| } |
| |
| /* Try to transform |
| (set (REGX) (CONST (PLUS (SYMBOL_REF) (CONST_INT A)))) |
| ... |
| (set (REGY) (CONST (PLUS (SYMBOL_REF) (CONST_INT B)))) |
| to |
| (set (REGX) (CONST (PLUS (SYMBOL_REF) (CONST_INT A)))) |
| ... |
| (set (REGY) (CONST (PLUS (REGX) (CONST_INT B-A)))) */ |
| if ((GET_CODE (src) == SYMBOL_REF |
| || (GET_CODE (src) == CONST |
| && GET_CODE (XEXP (src, 0)) == PLUS |
| && GET_CODE (XEXP (XEXP (src, 0), 0)) == SYMBOL_REF |
| && CONST_INT_P (XEXP (XEXP (src, 0), 1)))) |
| && dbg_cnt (cse2_move2add)) |
| { |
| rtx sym, off; |
| |
| if (GET_CODE (src) == SYMBOL_REF) |
| { |
| sym = src; |
| off = const0_rtx; |
| } |
| else |
| { |
| sym = XEXP (XEXP (src, 0), 0); |
| off = XEXP (XEXP (src, 0), 1); |
| } |
| |
| /* If the reg already contains the value which is sum of |
| sym and some constant value, we can use an add2 insn. */ |
| if (move2add_valid_value_p (regno, mode) |
| && reg_base_reg[regno] < 0 |
| && reg_symbol_ref[regno] != NULL_RTX |
| && rtx_equal_p (sym, reg_symbol_ref[regno])) |
| changed |= move2add_use_add2_insn (mode, reg, sym, off, insn); |
| |
| /* Otherwise, we have to find a register whose value is sum |
| of sym and some constant value. */ |
| else |
| changed |= move2add_use_add3_insn (mode, reg, sym, off, insn); |
| |
| continue; |
| } |
| } |
| |
| for (note = REG_NOTES (insn); note; note = XEXP (note, 1)) |
| { |
| if (REG_NOTE_KIND (note) == REG_INC |
| && REG_P (XEXP (note, 0))) |
| { |
| /* Reset the information about this register. */ |
| int regno = REGNO (XEXP (note, 0)); |
| if (regno < FIRST_PSEUDO_REGISTER) |
| { |
| move2add_record_mode (XEXP (note, 0)); |
| reg_mode[regno] = VOIDmode; |
| } |
| } |
| } |
| note_stores (PATTERN (insn), move2add_note_store, insn); |
| |
| /* If INSN is a conditional branch, we try to extract an |
| implicit set out of it. */ |
| if (any_condjump_p (insn)) |
| { |
| rtx cnd = fis_get_condition (insn); |
| |
| if (cnd != NULL_RTX |
| && GET_CODE (cnd) == NE |
| && REG_P (XEXP (cnd, 0)) |
| && !reg_set_p (XEXP (cnd, 0), insn) |
| /* The following two checks, which are also in |
| move2add_note_store, are intended to reduce the |
| number of calls to gen_rtx_SET to avoid memory |
| allocation if possible. */ |
| && SCALAR_INT_MODE_P (GET_MODE (XEXP (cnd, 0))) |
| && REG_NREGS (XEXP (cnd, 0)) == 1 |
| && CONST_INT_P (XEXP (cnd, 1))) |
| { |
| rtx implicit_set = |
| gen_rtx_SET (XEXP (cnd, 0), XEXP (cnd, 1)); |
| move2add_note_store (SET_DEST (implicit_set), implicit_set, insn); |
| } |
| } |
| |
| /* If this is a CALL_INSN, all call used registers are stored with |
| unknown values. */ |
| if (CALL_P (insn)) |
| { |
| rtx link; |
| |
| for (i = FIRST_PSEUDO_REGISTER - 1; i >= 0; i--) |
| { |
| if (call_used_regs[i]) |
| /* Reset the information about this register. */ |
| reg_mode[i] = VOIDmode; |
| } |
| |
| for (link = CALL_INSN_FUNCTION_USAGE (insn); link; |
| link = XEXP (link, 1)) |
| { |
| rtx setuse = XEXP (link, 0); |
| rtx usage_rtx = XEXP (setuse, 0); |
| if (GET_CODE (setuse) == CLOBBER |
| && REG_P (usage_rtx)) |
| { |
| unsigned int end_regno = END_REGNO (usage_rtx); |
| for (unsigned int r = REGNO (usage_rtx); r < end_regno; ++r) |
| /* Reset the information about this register. */ |
| reg_mode[r] = VOIDmode; |
| } |
| } |
| } |
| } |
| return changed; |
| } |
| |
| /* SET is a SET or CLOBBER that sets DST. DATA is the insn which |
| contains SET. |
| Update reg_set_luid, reg_offset and reg_base_reg accordingly. |
| Called from reload_cse_move2add via note_stores. */ |
| |
| static void |
| move2add_note_store (rtx dst, const_rtx set, void *data) |
| { |
| rtx_insn *insn = (rtx_insn *) data; |
| unsigned int regno = 0; |
| scalar_int_mode mode; |
| |
| /* Some targets do argument pushes without adding REG_INC notes. */ |
| |
| if (MEM_P (dst)) |
| { |
| dst = XEXP (dst, 0); |
| if (GET_CODE (dst) == PRE_INC || GET_CODE (dst) == POST_INC |
| || GET_CODE (dst) == PRE_DEC || GET_CODE (dst) == POST_DEC) |
| reg_mode[REGNO (XEXP (dst, 0))] = VOIDmode; |
| return; |
| } |
| |
| if (GET_CODE (dst) == SUBREG) |
| regno = subreg_regno (dst); |
| else if (REG_P (dst)) |
| regno = REGNO (dst); |
| else |
| return; |
| |
| if (!is_a <scalar_int_mode> (GET_MODE (dst), &mode)) |
| goto invalidate; |
| |
| if (GET_CODE (set) == SET) |
| { |
| rtx note, sym = NULL_RTX; |
| rtx off; |
| |
| note = find_reg_equal_equiv_note (insn); |
| if (note && GET_CODE (XEXP (note, 0)) == SYMBOL_REF) |
| { |
| sym = XEXP (note, 0); |
| off = const0_rtx; |
| } |
| else if (note && GET_CODE (XEXP (note, 0)) == CONST |
| && GET_CODE (XEXP (XEXP (note, 0), 0)) == PLUS |
| && GET_CODE (XEXP (XEXP (XEXP (note, 0), 0), 0)) == SYMBOL_REF |
| && CONST_INT_P (XEXP (XEXP (XEXP (note, 0), 0), 1))) |
| { |
| sym = XEXP (XEXP (XEXP (note, 0), 0), 0); |
| off = XEXP (XEXP (XEXP (note, 0), 0), 1); |
| } |
| |
| if (sym != NULL_RTX) |
| { |
| move2add_record_sym_value (dst, sym, off); |
| return; |
| } |
| } |
| |
| if (GET_CODE (set) == SET |
| && GET_CODE (SET_DEST (set)) != ZERO_EXTRACT |
| && GET_CODE (SET_DEST (set)) != STRICT_LOW_PART) |
| { |
| rtx src = SET_SRC (set); |
| rtx base_reg; |
| unsigned HOST_WIDE_INT offset; |
| int base_regno; |
| |
| switch (GET_CODE (src)) |
| { |
| case PLUS: |
| if (REG_P (XEXP (src, 0))) |
| { |
| base_reg = XEXP (src, 0); |
| |
| if (CONST_INT_P (XEXP (src, 1))) |
| offset = UINTVAL (XEXP (src, 1)); |
| else if (REG_P (XEXP (src, 1)) |
| && move2add_valid_value_p (REGNO (XEXP (src, 1)), mode)) |
| { |
| if (reg_base_reg[REGNO (XEXP (src, 1))] < 0 |
| && reg_symbol_ref[REGNO (XEXP (src, 1))] == NULL_RTX) |
| offset = reg_offset[REGNO (XEXP (src, 1))]; |
| /* Maybe the first register is known to be a |
| constant. */ |
| else if (move2add_valid_value_p (REGNO (base_reg), mode) |
| && reg_base_reg[REGNO (base_reg)] < 0 |
| && reg_symbol_ref[REGNO (base_reg)] == NULL_RTX) |
| { |
| offset = reg_offset[REGNO (base_reg)]; |
| base_reg = XEXP (src, 1); |
| } |
| else |
| goto invalidate; |
| } |
| else |
| goto invalidate; |
| |
| break; |
| } |
| |
| goto invalidate; |
| |
| case REG: |
| base_reg = src; |
| offset = 0; |
| break; |
| |
| case CONST_INT: |
| /* Start tracking the register as a constant. */ |
| reg_base_reg[regno] = -1; |
| reg_symbol_ref[regno] = NULL_RTX; |
| reg_offset[regno] = INTVAL (SET_SRC (set)); |
| /* We assign the same luid to all registers set to constants. */ |
| reg_set_luid[regno] = move2add_last_label_luid + 1; |
| move2add_record_mode (dst); |
| return; |
| |
| default: |
| goto invalidate; |
| } |
| |
| base_regno = REGNO (base_reg); |
| /* If information about the base register is not valid, set it |
| up as a new base register, pretending its value is known |
| starting from the current insn. */ |
| if (!move2add_valid_value_p (base_regno, mode)) |
| { |
| reg_base_reg[base_regno] = base_regno; |
| reg_symbol_ref[base_regno] = NULL_RTX; |
| reg_offset[base_regno] = 0; |
| reg_set_luid[base_regno] = move2add_luid; |
| gcc_assert (GET_MODE (base_reg) == mode); |
| move2add_record_mode (base_reg); |
| } |
| |
| /* Copy base information from our base register. */ |
| reg_set_luid[regno] = reg_set_luid[base_regno]; |
| reg_base_reg[regno] = reg_base_reg[base_regno]; |
| reg_symbol_ref[regno] = reg_symbol_ref[base_regno]; |
| |
| /* Compute the sum of the offsets or constants. */ |
| reg_offset[regno] |
| = trunc_int_for_mode (offset + reg_offset[base_regno], mode); |
| |
| move2add_record_mode (dst); |
| } |
| else |
| { |
| invalidate: |
| /* Invalidate the contents of the register. */ |
| move2add_record_mode (dst); |
| reg_mode[regno] = VOIDmode; |
| } |
| } |
| |
| namespace { |
| |
| const pass_data pass_data_postreload_cse = |
| { |
| RTL_PASS, /* type */ |
| "postreload", /* name */ |
| OPTGROUP_NONE, /* optinfo_flags */ |
| TV_RELOAD_CSE_REGS, /* tv_id */ |
| 0, /* properties_required */ |
| 0, /* properties_provided */ |
| 0, /* properties_destroyed */ |
| 0, /* todo_flags_start */ |
| TODO_df_finish, /* todo_flags_finish */ |
| }; |
| |
| class pass_postreload_cse : public rtl_opt_pass |
| { |
| public: |
| pass_postreload_cse (gcc::context *ctxt) |
| : rtl_opt_pass (pass_data_postreload_cse, ctxt) |
| {} |
| |
| /* opt_pass methods: */ |
| virtual bool gate (function *) { return (optimize > 0 && reload_completed); } |
| |
| virtual unsigned int execute (function *); |
| |
| }; // class pass_postreload_cse |
| |
| unsigned int |
| pass_postreload_cse::execute (function *fun) |
| { |
| if (!dbg_cnt (postreload_cse)) |
| return 0; |
| |
| /* Do a very simple CSE pass over just the hard registers. */ |
| reload_cse_regs (get_insns ()); |
| /* Reload_cse_regs can eliminate potentially-trapping MEMs. |
| Remove any EH edges associated with them. */ |
| if (fun->can_throw_non_call_exceptions |
| && purge_all_dead_edges ()) |
| cleanup_cfg (0); |
| |
| return 0; |
| } |
| |
| } // anon namespace |
| |
| rtl_opt_pass * |
| make_pass_postreload_cse (gcc::context *ctxt) |
| { |
| return new pass_postreload_cse (ctxt); |
| } |